1. Field of the Invention
The present invention relates to a method for controlling the operation of a sliver processing textile machine such as a spinning machine or the like. Particularly, the present invention is concerned with a method for judging the quality of sliver in a textile machine, the present method being capable of judging whether a spindle itself is defective or not, or which spindle is in a worse state of operation.
2. Prior Art
In a spinning machine for processing sliver into yarn, a single machine frame is provided with a large number of spindles (spinning units) for spinning. And each spindle is provided with a draft unit for drawing out sliver, a nozzle for spinning the drawn sliver into yarn, a take-up unit for winding the spun yarn to a package, and a yarn clearer for monitoring yarn, for example, detecting a yarn defect (slub) between the nozzle and the take-up unit.
Prior to the process of processing sliver into yarn there is a sliver producing process, and for the supply of sliver from the sliver producing equipment to the spinning machine there is used a cylindrical container, called a can. In an ordinary textile machine there is fed one can for each spindle, and a single replacement of a can permits the production of yarn over 2 to 3 days at the associated spindle.
In the spinning machine, the state of operation and the quality of yarn are detected with respect to each spindle and statistics are taken for the thus-detected information. For example, the number of times of stop is detected, and from the yarn thickness is detected the degree of change (uniformity) in yarn unevenness. The number of times of stop involves not only the number of times of stop based on full-loading or forced stop but also the number of times (or percentage) of slub breakage or of natural yarn breakage. Whether the operating condition of each spindle is good or bad can be judged from yarn quality information, including the breakage of yarn, uniformity, etc. As to a spindle involving bias in its yarn quality information, it can be estimated that there will be some defect. The number of times of slub breakage indicates how many times yarn has been cut with a cutter provided for each spindle in the event of occurrence of a yarn defect (e.g. nep, thin or thick).
The quality of yarn depends also on the quality of sliver as a feedstock. Therefore, when sliver of poor quality is fed, a bad result will appear also in the foregoing yarn quality information. In this case, even if a certain spindle is estimated to be defective on the basis of worsening of its yarn quality information and inspection and adjustment of the spindle are made, it will be impossible to find out any defect and no improvement will be recognized, that is, the work required for the inspection and adjustment becomes wasteful.